For electronic devices, miniaturization can provide significant advantages such as, for example, improved portability and/or reduced costs for storage, packaging, and/or transportation. However, miniaturization of an electronic device can be hindered by various physical constraints.
For example, in an electronic device, a gap having a sufficient width between two conductive units may be required to enable the electronic device to satisfy one or more performance requirements. The performance requirements can include one or more of electromagnetic wave transmission efficiency, radio signal reception efficiency, heat dissipation efficiency, etc. If the gap is narrowed for miniaturizing the electronic device, the performance of the electronic device can be compromised. If the gap is enlarged to improve the performance of the electronic device, the form factor of the electronic device can become undesirably large.
Techniques have been developed to physically widen the gap without enlarging the electronic device. However, the performance of the electronic device can be unacceptable in some situations when such prior art techniques are employed. A gap in a prior-art electronic device and a prior-art gap-widening arrangement are discussed with reference to FIGS. 1A-B.
FIG. 1A illustrates a gap 104 between two conductive units, for example, antenna 102 and ground 108, of a first example prior-art electronic device. Antenna 102 and ground 108 can be disposed on board 100. Board 100 can be disposed inside the first example prior-art electronic device and can have a limited surface area for accommodating various components. Antenna 102 can be configured to transmit electromagnetic waves, such as radio waves or microwaves, generated by a generator 106. Alternatively or additionally, antenna 102 can be configured to receive electromagnetic waves.
As well known in the art, gap 104 with a sufficient width, as illustrated by width 114, may be required so that transmission and/or reception of electromagnetic waves can satisfy one or more requirements such as efficiency, pattern shape, interference, mismatch, etc. Physically increasing width 114 of gap 104 can reduce the capacitance in gap 104, thereby freeing antenna 102 to radiate. Given the limited dimensions of board 100 (and required dimensions of ground 108), width 114 can be increased by, for example, physically reducing width 112 of antenna 102. However, reducing width 112 can have a significant impact on the radiation characteristics of antenna 102. As a result, the transmission and/or reception efficiency can be reduced, for example. Further, reducing width 112 can change the resonance frequency of antenna 102 as well as reducing the bandwidth of antenna 102. An example of a conventional technique for physically reducing the dimensions of an antenna is dielectric loading. This approach is discussed with reference to FIG. 1B herein below.
FIG. 1B illustrates, in a second example prior-art electronic device, dielectric loading component 156 disposed on antenna 152 for reducing width 162 of antenna 152, thereby enabling an increase in width 164 of gap 154 between antenna 152 and ground 108. Dielectric loading component 156 can be configured to reduce the resonant frequency of antenna 152, thereby enabling dimensions (e.g., width 162) of antenna 152 to be reduced. Accordingly, width 164 of gap 154 can be widened in order to reduce the aforementioned capacitive effects. However, reducing the width 162 of antenna 152 can cause a significant reduction of the radiation efficiency of antenna 152 itself. In some applications, the efficiency improvement resulted from a widened gap 154 may not be sufficient to compensate for the aforementioned reductions. In these situations, the transmission and/or reception efficiency and bandwidth of the second example prior-art electronic device can be rendered unacceptable when the width of the antenna is reduced.